Generic Name

Vibegron

Brand Names

GEMBIL in the U.S. and VIBEGRON elsewhere) is a selective, oral β3-adrenergic receptor agonist approved for the management of *overactive bladder* (OAB) with urgency, urge urinary incontinence (UUI), and frequency.

Mechanism

• Selective β3-adrenergic receptor agonist activates urothelial β3 receptors.
• Promotes relaxation of the detrusor muscle during the storage phase, increasing bladder capacity.
• Enhances anticholinergic tone in the bladder, reducing involuntary contractions.
• Minimal cross‑reactivity with β1 and β2 receptors → lower cardiovascular side‑effect profile.

Pharmacokinetics

Indications

• Overactive bladder symptoms: urgency, urge urinary incontinence, and increased daytime frequency in adults ≥18 years.
• Suitable for patients who:
• Prefer a once‑daily oral therapy.
• Have inadequate response or tolerance to anticholinergics or detrusor antimuscarinics.

Contraindications

• Contraindications:
• Severe renal impairment (CrCl < 15 mL/min) or end‑stage renal disease.
• Untreated symptomatic hyperthyroidism.
• Known hypersensitivity to *vibegron* or any excipient.
• Warnings:
• Cardiovascular: May cause elevations in systolic/diastolic BP (~5–10 mmHg) and mild tachycardia; monitor blood pressure in patients with uncontrolled hypertension or cardiovascular disease.
• Drug interactions: CYP3A4 inhibitors/inducers (e.g., itraconazole, rifampin) can alter plasma concentrations; adjust therapy accordingly.
• Drug–drug interactions: Concurrent anticholinergic medication use may amplify bladder side effects; assess cumulative anticholinergic burden.

Dosing

• Initial dose: 75 mg orally once daily (evening or morning).
• Maintenance dose: 150 mg once daily if additional symptom control is needed after ≥35 days of stable dosing.
• Titration: Not required; consider starting at 75 mg if patient has cardiovascular risk or is older than 75 years.
• Administration: With or without food; take same time each day.
• Non‑adherence: Missed dose can be taken when remembered; do NOT double‑dose to compensate.

Adverse Effects

Patient counseling: Inform about possible mild headache and nasal congestion; advise to report any chest pain, palpitations, or significant BP change.

Monitoring

• Baseline: BP, HR, serum creatinine, eGFR, and thyroid function test if clinically indicated.
• During therapy:
• BP and HR at first visit and after 4–6 weeks if baseline BP ≥ 140/90 mmHg.
• Renal function annually; earlier if renal impairment suspected.
• Assess OAB symptom score (OABSS) every 4–8 weeks to gauge efficacy.
• Safety labs: No mandatory lab monitoring unless concomitant high cardiovascular risk or renal compromise.

Clinical Pearls

• β3 Selectivity ≠ Lack of Cardiovascular Effects – Although cardio‑selective, it can still modestly raise BP; monitor in hypertensive or cardiac patients.
• Titration Flexibility – The 75 mg–150 mg range allows individualized risk‑benefit tailoring, especially in frail elderly patients.
• Non‑Cognitive Side‑Effect Profile – Unlike antimuscarinics, *vibegron* has minimal CNS manifestations; ideal in patients with cognitive decline.
• Drug‑Drug Interaction Check – Co‑administration with potent CYP3A4 inhibitors requires dose adjustment (reduce to 75 mg once daily).
• Adherence Boost – Its once‑daily dosing and lower anticholinergic burden improve adherence compared to mirabegron and antimuscarinics.

References

1. FDA Approval Letter, *Vibegron* (2023).

2. European Medicines Agency Summary of Product Characteristics, *Vibegron* (2023).

3. Clinical pharmacokinetics of β3 agonists, *Pharmacol Rev* (2022).